Spatial frequency and orientation tuning dynamics in area V1
AUTOR(ES)
Mazer, James A.
FONTE
The National Academy of Sciences
RESUMO
Spatial frequency (SF) and orientation tuning are intrinsic properties of neurons in primary visual cortex (area V1). To investigate the neural mechanisms mediating selectivity in the awake animal, we measured the temporal dynamics of SF and orientation tuning. We adapted a high-speed reverse-correlation method previously used to characterize orientation tuning dynamics in anesthetized animals to estimate efficiently the complete spatiotemporal receptive fields in area V1 of behaving macaques. We found that SF and orientation tuning are largely separable over time in single neurons. However, spatiotemporal receptive fields also contain a small nonseparable component that reflects a significant difference in response latency for low and high SF stimuli. The observed relationship between stimulus SF and latency represents a dynamic shift in SF tuning, and suggests that single V1 neurons might receive convergent input from the magno- and parvocellular processing streams. Although previous studies with anesthetized animals suggested that orientation tuning could change dramatically over time, we find no substantial evidence of dynamic changes in orientation tuning.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=122244Documentos Relacionados
- Spatial and temporal frequency selectivity of neurones in visual cortical areas V1 and V2 of the macaque monkey.
- Comparison of Spatial Summation Properties of Neurons in Macaque V1 and V2
- Spatial frequency tuning of orientation-discontinuity-sensitive corticofugal feedback to the cat lateral geniculate nucleus.
- Spatial vision of the achromat: spatial frequency and orientation-specific adaptation.
- Representation of spatial frequency and orientation in the visual cortex